I am working on a project that contains lots of images that makes the size of my app more than 30M. So I want to upload all my images on a server and allow the user to download those images to the SD card onclick, I mean when the user click a button to access a certain images it checks first if the image is available on the SD card, if not then download it. However, I am not familiar with some ideas1. Creating a file on the SD card that is accessible by my app.2. Establishing an active link to download a media to a certain file on the SD card.